Lands a mercy!

Interested in the origin of the phrase, "Lands a mercy!"

It's a euphemised version of "Lord have mercy!" (which was often pronounced as Lord 'a' mercy") Victorian writers often made English working-class female characters such as cooks and maids cry "Lawks-a-mussy", which is the same thing. The phrase "Landsakes!" has a similar origin, too. (VSD)